A shadowy figure in a wave near children swimming at a southern California beach has experts disagreeing .

Discovery Channel shark expert Jeff Kurr calls it a great white shark , but shark expert David Shiffman believes it was a dolphin .

The beast was caught on camera lurking near June Emerson 's 12-year-old son and three young friends as they played in the Manhattan Beach surf Friday afternoon .

The difference in the experts ' opinions centers on how they view the tail .

`` This is not a #shark photobombing kids . This is a dolphin , '' Shiffman tweeted Monday .

Shiffman , a recognized shark expert , noted in a Facebook posting that `` the tail is flat , '' like a dolphin , and unlike a shark .

But in an interview with CNN , Kurr concluded it was `` a juvenile great white shark about 10 to 12 feet long . ''

`` I would say based on the shape of the dorsal fin , which is more straight , that shows me it 's a great white shark , '' Kurr said . `` Plus , the fact that that particular beach has become the epicenter for white shark activity , I would say it 's definitely a white shark . ''

Emerson told CNN that it was n't until on the way home from the beach that her son spotted the creature in one of the photos she took that afternoon .

She remembers seeing dolphins in the water , but no sharks . Emerson told her son that it was a dolphin so as not to scare him away from the beach where they often swim .

There are plenty of great white sharks in the southern California surf , but they pose no danger to beachgoers , according to Randy Hamilton , a shark expert with California 's Monterey Bay Aquarium .

`` I just go back to the last 50 years on how many great white sharks have actually caused a death in southern California , '' Hamilton said . `` I only know of one incident where someone got a nip on the foot . ''

The great whites around southern California are juveniles , also known as `` young of the year . '' At less than 18 months old , they only eat fish , Hamilton said . When the sharks approach adulthood , they relocate to the cooler waters near San Francisco where they change their diets to mammals -- sea lions and seals , he said .

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It 's `` a juvenile great white shark about 10 to 12 feet long , '' expert Jeff Kurr says

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`` The tail is flat , '' like a dolphin -- not a shark , expert David Shiffman says

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June Emerson snapped the photo of her son and friends playing in the surf

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Great white sharks are no danger to southern California swimmers , expert says